Papers by Keyword: Non-Destructive Testing

Abstract: In this paper, we present a nondestructive Testing by sensor Eddy current is used as a tool to control cracks and micro-cracks in materials. A new method for computing by measuring and testing related 3D Eddy currents is considered. In the process, a Potential Magnetic Vector is provided on the basis of formulations taken from the theoretical set up. Thus, results of relevant applications are obtained to check the theory consistency. A simulation by a numerical approach using Finite element discretization of 3-D Eddy Current governing equations is employed to detect cracks and damaged zones in materials and eventually to study their propagation.

Abstract: This paper describes a typical 3D X-ray micro computed tomography (microCT) analysis of light metal parts, from a radio controlled airplane engine. This case study shows the power of 3D X-ray inspection and analysis for this type of material, including information about the size and location of casting defects, the location of turbine blade balancing weights and dimensional measurements indicating the axle was not perfectly centre. Advantages and limitations of the method for light metals are described in general

Abstract: Acoustic emission (AE) is current trend of non-destructive monitoring methods. It suits perfectly for supporting of fatigue tests. The method is also applicable in monitoring of quasi-static tests. AE helps the engineers to understand the degradation process in the tested object and also keep track of the failures. This article offers an insight into the practical experience with acoustic emission. Tests of three different composite structures (wing, fuselage and hull panel) were chosen to illustrate the application of AE monitoring system during fatigue and quasi-static tests. These tests have shown that accuracy of localization is sufficient to identify damaged areas. Moreover, the system may offer an early warning of upcoming failure.

Abstract: Adhesion assessment between concrete layers with the use of the non-destructive ultrasonic pulse velocity (UPV) method has been described in the article. Two-layer concrete elements, obtained by drilling the core from a large size multilayer element, were the object of testing. The ultrasonic wave velocity of the element and the materials of which its layers were made were assigned for each element. On that basis, the comparative velocity i.e. the velocity at which an ultrasonic wave going through the boundary surface of layers wouldn’t cause any change in the velocity, was determined. The ratio of the two velocities has been compared to adhesion values obtained through the semi-destructive pull-off method. It was revealed that when the ratio of the ultrasonic wave velocity of the element to comparative velocity increases, the pull-off adhesion value also increases.

Abstract: The comprehensive characterization of the change in metallic materials’ microstructure due to an applied load is of prime importance for the understanding of basic fatigue mechanisms or more general damage evolution processes. If those mechanisms and processes are to be understood to a much greater extent, advanced fatigue life calculation methods being far away from linear damage accumulation models, have to be realized providing more than “classic fatigue data” only.
Among others the PHYBAL (physically based fatigue life calculation) method including current enhancements and a thereon-based development named SteBLife (step-bar fatigue life approach) have been developed over the last 10 years. These methods allow the efforts in experimentation to be reduced by more than 90 % and therefore offer the possibility to take further fatigue relevant parameters into account. This therefore allows a variety of S,N-curves dependent on those fatigue relevant parameters to be generated with those methods easily establishing a multidimensional dataset. To just name a few examples of those parameters such as the influence of temperature, loading conditions, geometry as well as thermal and mechanical ageing processes on the fatigue behavior can now be calculated in accordance to a process being straightforward leading to an important step with regard to improving the efficiency of assessing structural components. Consequently, safety factors can be defined more in accordance to structural needs, being of highest interest with respect to the increasing number of ageing infrastructure such as highways, bridges or others.
A lot of this ageing infrastructure has a strong need to be managed with respect to its structural integrity and the engineering community therefore tries the residual life of this infrastructure to be determined as appropriate as possible. In that context non-destructive testing parameters are increasingly considered to characterize a metallic material’s microstructure allowing more precise information to be obtained regarding the actual damage condition and the integrity of a component.
The paper will address the high capability of non-destructive testing techniques for the evaluation of damage evolution processes also with respect to mechanism based fatigue as well as residual life calculations according to PHYBAL and SteBLife.

Abstract: NDT impedance spectroscopy method was used to characterize a Cetris wood-cement chipboard. Dry specimen pre-stress and post-stress cycle tan δ (f) spectrum variances were observed. Effects of potential dielectric losses and the predominance of the polarization and conductivity components in various regions of the impedance spectrum of samples after frozen stress cycle are described. The method reproducibility has been verified by multiple measurements.

Abstract: Residual stresses typically are generated during the manufacturing process of mechanical components. The non-destructive techniques are quite sensitive to these residual stresses, and to microstructural changes resulting from thermal cycling. In this work, samples of API 5L X80 steel were exposed to several conditions of cooling, under water, air and oil, thus obtaining different microstructures and different levels of residual stresses. The residual stress measurements were made using the methods of Magnetic Barkhausen Noise and X-ray diffraction.

Abstract: In present paper, possibilities for identification and verification of closure welds were discussed. It might be applied for nonproliferation purposes, where validity and reliability of verification are often crucial issue. Methodology of ultrasonic testing and signal processing procedure were proposed. Through set of experiments, the validity of proposed solution was approved.

Abstract: The article is to study the development of computer-aided design of X-ray microtomography - the device for investigating the structure and construction three-dimensional images of organic and inorganic objects on the basis of shadow projections. This article provides basic information regarding CAD of X-ray microtomography and a scheme consisting of three levels. The article also shows basic relations of X-ray computed tomography, the generalized scheme of a X-ray microtomographic scanner. The methods of X-ray imaging of the spatial microstructure and morphometry of materials are described. The main characteristics of an X-ray microtomographic scanner, the X-ray source, X-ray optical elements and mechanical components of the positioning system are shown. The block scheme and software functional scheme for intelligent neural network system of analysis of the internal microstructure of objects are presented. The method of choice of design parameters of CADof X-raymicrotomography is aimed at improving the quality of design and reduce of costs of it. It is supposed to reduce the design time and eliminate the growing number of engineers involved in development and construction of X-ray microtomographic scanners.

Abstract: The aim of this paper is to evaluate the possibility of using the nonlinear ultrasonic spectroscopy with a single exciting harmonic frequency for concrete carbonation monitoring. Carbonation of concrete is related with the corrosion of steel reinforcement and with carbonation shrinkage. Due to the conditions in the laboratory were as close as possible to practical terms, we used reinforced concrete samples. For the research, the concrete beams with one standard reinforcing bar passing through the centre of the sample were made. Prepared samples were exposed to an atmosphere with increased carbon dioxide content. The measurements using the nonlinear ultrasonic spectroscopy with a single exciting harmonic frequency were realized before and after carbonation of concrete.